Rather than malloc, ExtractToMemory, and write.
Also fix the tmpfile error check (tmpfile returns NULL on failure),
and improve error reporting.
Bug: 19765860
Change-Id: I236923e883128083377607f1519bb2e27b8f03f8
If you don't have android-info.txt in your zip file, you're probably
not using a current fastboot binary anyway.
Change-Id: Ic721dc5f068f704c6792493d1e99f05f907678ba